Originally Posted by sdrucker
After all this time, I got busy, and installed and set up my UMM-6 with the appropriate 90 degree cal file. The biggest obstacle was getting my laptop to stay on the Geoforce Nvidia HDMI-equipped card, rather than default to the mobile display and give me dead eight channel HDMI audio and mic. I tried Keith's 'incantation', and it didn't work until I picked the Geoforce with extended desktop on both laptop and my VT50 display. Argh.,...,
Anyway, after running the Ratshack SPL to get 80 db, I came up with a noise floor in the mid-50s and maximum sensitivity of exactly 120 db. Should this be a concern, at the extreme of the 'normal' range?
Also, how many measurements are you guys taking to get a publishable average? Do you recommend concentrating on MLP or the Audyssey basic three to eight, if my focus is the three seats in the MLP?
I only had time earlier to run one for the subs with no Audyssey, output down 10 db for the sub LFE, and with no smoothing, there's a needle sharp 30 db null at 60 and approximately 90 Hz
. I hope it goes away when I do more measurements and bring in my Mythos ST (currently at 80 Hz, but I'll be curious to see how they look at 60 as well) for full range at 1/6 or 1/12, with Audyssey engaged and DEQ off. And I'm only on battery power....with OM and L/R+sub plots post-Audyssey at 1/12, those dips were much milder (not even -5 db).
Finally, is it good form to capture all speaker configurations of interest (e.g. L/R+subs) at a position and move on to the next position (then averaging each configuration by selectively picking the measurements), or getting all OCD and doing all X measurements by configuration, averaging, then moving on to the next configuration? I'd think the former, but as a REW neophyte, it doesn't hurt to check before I create 48 temporary files at one sitting LOL....
To add a bit to Keith's response:
A noise floor of ~50dB is as good as it gets with this mic. At this time, it is still unclear whether the higher noise floor (when compared with the balanced EMM-6, for example, which measures a noise floor of ~40dB) has any meaningfull impact on our measurements. I would guess that the waterfall might be impacted, but I am not sure.
As far as a measurement average is concerned, IMO the average has limited value. For example, when you are sitting in the MPL, what does an average response graph tell you about the sound you are hearing--nothing. I think that since we believe Audyssey is somehow averaging the 8 measurement positions to produce the smoothest response over the listening area, perhaps an 8-position average using REW would give us some insight into what Audyssey is doing. Perhaps this is true, but so what? If you do take a number of REW measurements at points outside of the MLP, it might reveal one or more points that exhibit an undesirable response anomaly. Such an anomaly, if at one of the 8 Audyssey measurement points, could be skewing the Audyssey calibration. Knowing this, you could either try to correct the anomaly, or "game" Audyssey by avoiding the anomaly during your calibration.
So, don't bother publishing the average. IMO, here are the six most meaningful measurements to publish in your first go-around (all taken from the MLP, with Audyssey on and DEQ off):
- Left+Right+Subs, 15-20,000Hz, 1/6 smoothing.
- Center+Subs, 15-20,000Hz, 1/6 smoothing
- Bass response 15-300Hz, no smoothing (using one of the two measurements above)
- Waterfall 20-300Hz, (also using one of the first two measurements)
- Impulse ETC graphs for the Left and Right speakers, measured individually, 20-20,000Hz, with subs off.
The first three measurements reflect what you are actually hearing at the MLP. For example, you never hear just the bass, or just the left speaker. If this first set of graphs indicates issues that you want to understand and resolve, that is the time to start drilling down into the detailed measurements, isolating single speakers, etc. Don't produce 48 measurements the first time around!
Of course, this is just my opinion, and I would enjoy hearing other viewpoints.